Infrastructure:

We were not handling POLLHUP notifications for event file descriptors.

Fix it by filtering entries in the events file descriptor array after
poll returns, refcounting mmaps so that when the last fd pointing to
a perf mmap goes away we do the unmap.

User visible:

Now 'record' and 'trace' properly exit when a target thread exits.

Arnaldo Carvalho de Melo (14):
  perf evlist: Introduce perf_evlist__filter_pollfd method
  perf tests: Add test for perf_evlist__filter_pollfd()
  perf evlist: Monitor POLLERR and POLLHUP events too
  perf evlist: We need to poll all event file descriptors
  perf evlist: Allow growing pollfd on add method
  perf tests: Add pollfd growing test
  perf kvm stat live: Use perf_evlist__add_pollfd() instead of local equivalent
  perf evlist: Introduce poll method for common code idiom
  tools lib api: Adopt fdarray class from perf's evlist
  perf evlist: Refcount mmaps
  tools lib fd array: Allow associating an integer cookie with each entry
  perf evlist: Unmap when all refcounts to fd are gone and events drained
  perf record: Filter out POLLHUP'ed file descriptors
  perf trace: Filter out POLLHUP'ed file descriptors

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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